EPA's Computational Toxicology Research

There are currently more than 80,000 chemicals listed or registered for use under EPA authorities, many of which have not been thoroughly assessed for the health and environmental risks. With hundreds more introduced into the marketplace every year, it is easy to see the enormous challenges facing EPA officials and others tasked with ensuring the sustainable production, use, and disposal of chemicals.

A mechanized, robot-driven chemical screening system run with Agency partners at the National Institutes of Health Chemical Genomics Center can effectively run 1,536 separate experiments at a time.

To meet those challenges, EPA researchers are leading the development of innovative new tools and technologies to evaluate the safety of chemicals, products and emerging materials. EPA computational toxicology researchers are using advances in exposure science, molecular and systems biology, chemistry, mathematical and computer modeling, and computer technology to predict chemical hazards and risk. In the process, they are ushering in a new generation of predictive tools to evaluate potential chemical risk to human health and the environment.

Tox21

EPA researchers and their partners conduct high-throughput chemical screening using robotics and a variety of other technologies available from a research partnership called Toxicity Testing in the 21st Century (“Tox21”). Tox21 is a collaborative federal research partnership uniting EPA, the National Institutes of Health, and the U.S. Food and Drug Administration to screen tens of thousands of chemicals.

The automated systems move small, specialized test plates, each with 1,536 tiny wells of liquid test solutions and containing human cells or proteins, through a series of computerized screening and analysis activities; in effect simultaneously running thousands of separate experiments at a time.

EPA’s computational toxicology research continued to make important strides in 2012.

Researchers analyzed automated, high-throughput screening data and developed high-throughput exposure predictions for over 1,000 chemicals of interest. “High-throughput” refers to the speed of chemical tests (assays) or predictions, defined as being capable of generating test results or predictions for hundreds to thousands of chemicals in just days or weeks. The researchers also analyzed chemical structures to identify which chemical properties are more likely to influence toxicity and exposure potential.

These accomplishments promise to deliver advanced methods that are not only higher performing and faster, but also far less costly to use.